End-To-End Packet Flow and Forwarding JN0-364 Practice Questions (Page 4)

Questions 16–20

1. 16foundation · easy

   In a typical MPLS LSP, what is the correct sequence of label operations from ingress to egress?

   • APush, swap, pop
   • BPush, pop, swap
   • CPop, swap, push
   • DSwap, push, pop
   Reveal Solution Discussion Select an answer first
2. 17foundation · easy

   After the egress LSR pops the final MPLS label, how does it forward the packet?

   • AIt uses the LFIB to find the outgoing label.
   • BIt forwards the packet to the next hop in the LSP.
   • CIt drops the packet because the label is gone.
   • DIt performs a lookup in the IP routing table.
   Reveal Solution Discussion Select an answer first
4. 18application · medium

   A network administrator is troubleshooting an MPLS forwarding issue on a transit LSR. The router receives a packet with an incoming label of 200. The LFIB contains the following entry: Incoming label 200, outgoing label 300, next hop 10.0.0.2, interface ge-0/0/2. What will the router do with this packet?

   • APush label 300 on top of label 200 and forward the packet out ge-0/0/2.
   • BDrop the packet because the incoming label is not in the LFIB.
   • CPop label 200 and forward the packet based on the IP destination address.
   • DSwap label 200 with label 300 and forward the packet out ge-0/0/2 to 10.0.0.2.
   Reveal Solution Discussion Select an answer first
5. 19application · medium

   A network engineer is configuring an ingress LSR to forward traffic from a customer edge (CE) router into an MPLS LSP. The CE sends IP packets destined to a prefix that is reachable via the LSP. What must the ingress LSR do to forward these packets into the MPLS network?

   • APerform a routing table lookup on the destination IP, find the LSP next hop, push the label advertised for that LSP, and forward out the appropriate interface.
   • BPop the top label and forward the packet based on the IP routing table to the next hop.
   • CPerform a label lookup on the incoming label, swap it with the outgoing label, and forward out the interface toward the next hop.
   • DEncapsulate the packet in a new IP header with the LSP destination address and forward it without a label.
   Reveal Solution Discussion Select an answer first
6. 20application · medium

   An egress LSR receives an MPLS packet with a label value of 300. The LFIB indicates that label 300 is the final label for the LSP. What will the egress LSR do with this packet?

   • APop label 300 and perform an IP routing table lookup on the destination address to forward the packet.
   • BDrop the packet because the label is not recognized.
   • CPush an additional label onto the packet and forward it to the destination.
   • DSwap label 300 with a new label and forward the packet to the next LSR.
   Reveal Solution Discussion Select an answer first